Manufacture of hollow bodies having projections protruding from the inner surface



A. SCHLICHTHAERLE EI'AL I MANUFACTURE OF HOLLOW BODIES HAVING PROJECTIONS Nov. 5, 1957 2,812,003

PROTRUDING FROM THE INNER SURFACE Filed Jan. 31, 1955 FIG. I62

United States Patent MANUFACTURE OF HOLLOW BODIES HAV- ING PROJECTIONS PROTRUDING FROM THE INNER SURFACE Anton Schlichthaerle, Friedrich Jennrich, and Walter Salzer, Ludwigshafen am Rhine, Germany, assignors to Badische Anilln- & Soda-Fabrik Aktiengesellschaft, Ludwigshafen am Rhine, Germany Application January 31, 1955, Serial No. 485,084

Claims priority, application Germany January 30, 1954 4 Claims. (Cl. 153-32) This invention relates to a method of forming a hollow body having tongue-like projections protruding from its inner surface and spaced inwardly from one end or both ends thereof.

It has been common practice to manufacture hollow bodies of any cross-section, preferably of circular cross section, with tongue-like projections which protrude from their inner surface and are spaced inwardly from the ends thereof by forming them from band sections provided with such projections by bending over surfaces which engage from outside into the end or ends of the hollow body to be formed which are not occupied by projections and serve during the bending at the same time as holder for the band section.

We have now found that the forming of a hollow body, which is preferably circular, can be carried out from an endless band or a sheet which has been provided with the desired projections instead of from a band section. For this purpose the band or sheet provided with the projections is pressed, in a length corresponding to the circumference of the hollow body to be formed, against surfaces of the form of the desired hollow body and the length thus deformed is separated from the band or sheet after partial formation of the hollow body.

The forming of the hollow body can be effected by bending a corresponding length of the band or sheet provided with the projections around a mandrel or two spaced opposed mandrels which engage laterally from outside into the end or ends of the hollow body to be formed which are not occupied by projections, the said mandrel or mandrels acting at the same time as holders for the band or sheet during the bending. The forming of the hollow body can also be achieved by winding a corresponding length of the band or sheet provided with the projections around a'mandrel or two spaced opposed mandrels which overlap only the zone or respectively the opposite zones of said length of the band or sheet adjacent the edge or edges being free of the projections. Another method of forming the holow body consists in curling a length of the band or sheet corresponding to the circumference of the hollow body to be formed within a hollow mould adapted to the desired cross-section of the hollow body. The hollow body can also be prepared by guiding the band or sheet around two spaced opposed mandrels by means of pressure rollers, said mandrels respectively overlapping only the opposite zones of the band length adjacent the edges which are free of projections.

Apparatus suitable for carrying out the method according to the present invention are shown diagrammatically and by way of example in Figures 1 to 4 of the accompanying drawings.

Fig. 1 is a vertical sectional view in the longitudinal direction of the band, in which the cut-off band section is shaped into a hollow cylindrical body by a pair, of dies;

, tions x.

Fig. la is a cross-sectional view taken on line II of Fig. 1;

Fig. 2 is a vertical sectional view in the longitudinal direction of the band, in which a band section is wound upon two spaced opposed mandrels to produce a hollow cylindrical body;

Fig. 2a is a cross-sectional view taken on line IIII of Fig. 2;

Fig. 3 is a vertical sectional view in the longitudinal direction of the band, in which a band section is rolled into a hollow cylindrical body by means of a concave-shaped movable plate;

Fig 3a is a cross-sectional view taken on line III--III of Fig. 3;

Fig. 4 is a vertical sectional view in the longitudinal direction of the band, in which a band section is shaped into a closed hollow cylindrical body by means of a number of paired rollers; and

Fig. 4a is a cross-sectional view taken on line IVIV of Fig. 4.

Generally speaking, with reference to Figs. 1 to 4, a band a is pushed forward over a punching block u having a plurality of recesses v, and beneath a press die i having a plurality of cutting or punching members w which register with the recesses v. The press die i in moving downwards engages the recesses v thus punching out projections x from band a in such a manner that the protruding portions x stand out from the lower surface of the band, while the upper surface of the band remains flat. Housed in the recesses v are ejectors s which are combined in a common reciprocatory motion with the press die 1' so that the two elements accomplish a common vertical reciprocatory movement. In moving upward the ejectors s lift the band a by pushing upwardly against the projec- The projections x are thus moved up to the plane of the punching block a so that the band can be moved forward without the projections snagging in or being detained by the recesses v.

In the arrangement illustrated in Figure 1, a band a, after it has been provided by means of a press die i with projections protruding from its surface, is pushed forward by a length which corresponds to the circumference of the hollow body to be formed, so that it abuts against a stop b and lies between a movable and a stationary pressure jaw c, d which are provided with recesses corresponding to the shape of the hollow body to be formed. By moving the jaw c which is provided with projections e, 1 towards one or two mandrels h which are laterally movable in the bearings t and are moved as far towards the length of the band or sheet to be deformed as the end or ends not occupied with projections of the hollow body to be formed will permit, the deformation is initiated by the projections e and f bending the length of the band or sheet to be deformed over the mandrel or mandrels. After one half of the hollow body has been thus preformed to the extent predetermined by the difference in height between the zenith of the mandrel or mandrels and the plane of the non-deformed endless band or sheet, cutting of this preformed length from the band or sheet takes place by a projection g formed as a knife on the jaw c. The jaw 0 together with the mandrel or mandrels h is then moved towards the'stationary jaw d and the formation of the hollow body completed. During the subsequent retraction of the jaw c, and of the mandrel or mandrels h, to their original position, the mandrel or mandrels is or are withdrawn from the end or ends of the hollow body unoccupied by projections and thus the hollow body is freed and can readily be removed from the apparatus, for example by means of compressed air.

In the apparatus illustrated in Figure 2, the endless band a provided with projections is grasped by one or two mandrels l journaled for lateral and rotary movement in bearing y and byrotation of the mandrels is .wound up in a length corresponding to the circumference of the mandrels while it is pressed against the same by a roller k. The separation of the length of the band to be deformed is elfected, after the winding process has been initiated, by a knife g which is associated with the press die i serving for the production of the projections.

Figure 3 illustrates an apparatus for deforming a band or sheet to a hollow body by curling a corresponding length of the band or sheet. The band a provided with projections is pushed into a box-like hollow chamber m formed by a stationary plate 11,, a movable plate 11 a stationary plate n, acting as a pressure surface and a movable slide 21,, the surfaces of plate 11 and the slide 11 facing the hollow chamber each being formed as a semicylindrical surface 0 or 0 The band pushed into the hollow chamber is engaged by the slide n moving towards it and rolled along the cylindrical surface 0,. By this longitudinal movement of the slide, first one half of the hollow body is formed by rolling and then the other half is formed by means of the stationary plate n,. The separation of the deformed length of band from the endless band is elfected shortly before the end of the rolling with the aid of a knife g associated with the press die i serving for preparing the projections. The finished hollow body is freed by the retraction of the slide 11, and the movable plate n,.

In the apparatus illustrated in Figure 4, the band a provided with projections is gripped by two rotating lower rollers p which engage into the ends of the hollow body to be formed, which are not provided with projections, and an upper roller q and rounded with the aid of a pressure roller r. The rollers p, q and r are journaled in the bearing z, roller p also being laterally movable therein. After initiation of the deformation, the length of band to be deformed is separated by a knife g which is associated with the pressure die i for the production of the projections. When the rounding of the separated band has been completed, the hollow body formed is freed by lateral displacement of the lower rollers p and removed from the apparatus.

,We claim:

1. A method of forming hollow cylindrical bodies from a continuous fiat band material, said bodies each having a set of tongue-like projections protruding from their inner surface and spaced inwardly from the ends thereof, which comprises: stamping and forming a set of said projections in a unit length of said flat band corresponding to the circumference of one of said bodies, said projections being spaced inwardly from the longitudinal edges of said band corresponding to the ends of one of said bodies; feeding said unit length of said band into a position for deformation against a cylindrical surface having the form of the hollow body, said surface being free of contact with said projections; partially deforming said unit length of said hand against said surface; and separating the partially deformed unit length from the band while simultaneously stamping and forming another set of said projections in a unit length of said band sequentially following said partially deformed unit length.

2. A method of forming hollow cylindrical bodies from a continuous flat band material, said bodies each having a set of tongue-like projections protruding from their inner surface and spaced inwardly from the ends thereof, which comprises: stamping and forming a set of said projections in a unit length of said flat band corresponding to the circumference of one of said bodies, said projections being spaced inwardly from the longitudinal edges of said band corresponding to the ends of one of said bodies; feeding said unit length of said band into a position for deformation against a cylindrical mandrel, said mandrel overlapping only the Zone of said band adjacent an edge thereof which is free of said projections; partially deforming said unit length of said band against said mandrel; and separating the partially deformed unit length from the band while simultaneously stamping and forming another set of projections in a unit length of said fiat band sequentially following said partially deformed unit length.

3. A method of forming hollow cylindrical bodies from a continuous flat band material, said bodies each having a set of tongue-like projections protruding from their inner surface and spaced inwardly from the ends thereof, which comprises: stamping and forming a set of said projections in a unit length of said flat band corresponding to the circumference of one of said bodies, said projections being spaced inwardly from the longitudinal edges of said band corresponding to the ends of one of said bodies; feeding said unit length of said band into a position for deformation against two spaced opposed cylindrical mandrels, said mandrels overlapping only the opposite Zones of said band adjacent said edges which are free of said projections; partially deforming said unit length of said band against said mandrels; and separating the partially deformed unit length from the band while simultaneously stamping and forming another set of projections in a unit length of said flat band sequentially following said partially deformed unit length.

4. A method of forming hollow cylindrical bodies from a continuous flat band material, said bodies each having a set of tongue-like projections protruding from their inner surface and spaced inwardly from the ends thereof, which comprises: stamping and forming a set of said projections in a unit length of said flat band corresponding to the circumference of one of said bodies, said projections being spaced inwardly from the longitudinal edges of said band corresponding to the ends of one of said bodies; feeding said unit length of said band into a position for deformation of said unit length around two spaced opposed cylindrical mandrels, said mandrels overlapping only the opposite zones of said band adjacent said edges which are free of said projections; partially deforming said unit length of said band by rounding said band between said mandrels and :at least two pressure rollers arranged consecutively on the periphery of said mandrels; separating the partially deformed unit length from the band while simultaneously stamping and forming another set of projections in a unit length of said flat band sequentially following said partially deformed unit length; and completing the deformation of said first-named unit length to produce one of said hollow bodies.

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